The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. These ICs include bipolar transistor devices. Bipolar transistor devices include NPN-type transistors and PNP-type transistors. As fabrication processes progress to technology nodes that are becoming increasingly small, it may be difficult to form an NPN-type transistor and a PNP-type transistor simultaneously. Often times, simultaneous formation of NPN-type and PNP-type transistors may require additional masks and/or separate process flows, both of which increase fabrication costs and slow down production.
Therefore, while existing methods of fabricating bipolar transistor devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.